关键词: 羽衣甘蓝, 克隆, 肉桂酸- 4 - 羟化酶(C4H), 突变, 序列分析

Abstract: A 2 431-bp full-length cinnamate-4-hydroxylase gene, BoC4H, was cloned from Brassica oleracea L. var. acephala DC. It contains 2 introns. ItsmRNA is 1 715 bp, encoding a deduced 481-amino-acid
polypeptide with wide homologies to C4Hs from other plants. It possesses cytochrome P450 conserved domains
and motifs such as the haem-iron binding motif, the E - R - R triad, the T-containing binding pocket motif
and the hinge motif necessary for optimal orientation of the enzyme. It also has most of the canonical C4H /
CYP73A5-featured substrate-recognition sites ( SRSs) and active site residues. But owing to a single2base de
letion at C₂₂₄₂ and subsequent frame shiftwithin the 3′coding region as compared with C4H genes from Arabidopsis thaliana and other p lants, BoC4H shows a 36-aa deletion /variation at its C-terminus, and the SRS6 motif together with active site residues therein are absent. Thus BoC4H may be of no function or low activity.
BoC4H is a membrane p rotein and is probably associated with endop lasmic reticulum. Its secondary structure
is dominated by alpha helices and random coils. Swiss-Model could not p redict its tertiary structure. B. oleracea contains a C4H gene family with at least 5 members.

Key words: Brassica oleracea L. var. acephala DC., Cloning, Cinnamate-4-hydroxylase ( C4H ), Mutation, Sequence analysis